Underground mining machines are commonly used around the world to extract minerals, metals and other materials from various hard and soft rock environments. One example of an underground mining machine is a jumbo drill, although many other types exist. The underground mining machine may include a reeling system that may include a power cable coupling a power source for the machine to a working implement of the machine. A cable reel may also be rotatably associated with the underground mining machine and be configured to coil and uncoil the power cable. Further, the reeling system may include a cable reel-motor rotationally engaged with the cable reel. The cable reel-motor may be configured to rotate the cable reel in a first direction when coiling the power cable and rotate the cable reel in a second direction when uncoiling the power cable.
While moving the underground mining machine in a reverse direction, a velocity at which the operator is moving the underground mining machine may be greater than a velocity at which the cable reel-motor is rotating the cable reel. In this instance, the operator may accidentally overrun the power cable, leading to damage and the need to repair or replace the power cable. Additionally, while moving the underground mining machine in a forward direction, and when an amount of the power cable still coiled around the cable reel is nearing its end, the velocity at which the operator is moving the underground mining machine may leave little time for the operator to stop the underground mining machine before breaking the connection between the power cable and the underground mining machine.
Although underground mining machine power cable winding and unwinding schemes are known, there is still room for improvement. For example, U.S. Pat. No. 6,119,837 to Tschurbanoff et al. discloses a hydraulic control system to regulate the rate at which the cable reel winds or unwinds the power cable as a function of machine speed. More specifically, as machine speed increases the mass flowrate of hydraulic fluid sent to a hydraulic motor rotatably engaged with the cable reel increases, and vice versa.
While arguably effective for its specific purposes, such prior art system only attempts to match cable reel speed with underground mining machine speed, failing to recognize a need to operate the underground mining machine in any different manner. Such system also relies on a fluid-based control system, and thus there may be lag between the underground mining machine speed and the cable reel speed, leading to sagging and stretching of the power cable. Also, as a result of such lag, the momentum of the machine may still be great enough that the machine continues to move even after receiving a machine stop signal. In this instance, the power cable may break away from the underground mining machine.